Endoscopic surgical procedures are routinely performed in order to accomplish various surgical tasks. In such a surgical procedure, small incisions or portals are made in the patient. An endoscope, which is a device that allows medical personnel to view the surgical site, is inserted into one of the portals. Surgical instruments used to perform other tasks are inserted into other portals. The surgeon views the surgical site through the endoscope to determine how to manipulate the surgical instruments in order to accomplish the desired procedure. An advantage of performing endoscopic surgery is that, since the portions of the body that are cut open are minimized, the portions of the body that need to heal after the surgery are likewise reduced. Moreover, during an endoscopic surgical procedure, only relatively small portions of the patient's internal organs and tissue are exposed to the open environment. This minimal opening of the patient's body lessens the extent to which a patient's organs and tissue are open to infection.
The ability to perform endoscopic surgery is enhanced by the development of powered surgical tools especially designed to perform such procedures. Once such tool is sold by the Assignee hereof under the trademark FORMULA®. This tool is in the form of a cylindrical handpiece designed to be held in the hand of the surgeon. The handpiece has a front or distal end provided with a coupling assembly for releasably holding a cutting accessory, and a motor disposed within a handpiece housing which drives the accessory. One such cutting accessory, often termed a “shaver”, includes a hub which defines the proximal end of the accessory and is appropriately configured to cooperate with the coupling assembly of the handpiece to lock the accessory thereto, an elongated and tubular housing element having a proximal end fixed to the hub, and an elongated cutting element including a drive shaft disposed within the housing element. When the accessory is attached to the handpiece, the handpiece motor couples to the drive shaft of the accessory and moves same relative to the outer housing element. The handpiece motor is selectively actuable to drive the accessory drive shaft so as to cause a desired cutting action at the distal end of the accessory. The handpiece is associated with a control unit which controls the functioning thereof, and is actuated by the user via appropriate buttons provided on the handpiece itself, or alternatively directly at the control unit.
In an endoscopic surgical procedure, irrigating fluid is introduced into the surgical site. This fluid serves as a transport media for removing tissue and debris from the surgical site. In order to remove the irrigating fluid and the material contained therein, the above handpiece and the various accessories which are usable therewith together define a suction conduit. A suction pump is connected to the handpiece to provide the suction force needed for drawing the fluid and material away from the surgical site. In order to control the suction flow through the accessory and the handpiece, the handpiece is provided with a manually operated valve which is manipulated by the surgeon to control suction of material away from the surgical site.
Mechanical cutting accessories, such as the shaver discussed above, are commonly used in arthroscopic procedures, and allow for the resection of hard and soft bodily tissues, for example, those found within the knee, shoulder and other joints. In such a cutting accessory, the outer housing element defines a window or opening at the distal end, which window is defined by an edge of the wall of the outer housing element. The cutting element drive shaft at the distal end thereof also includes a cutting head having a window defined by an edge of the wall of the cutting head, and when the cutting head is disposed within the housing element, the cutting head window is positioned adjacent the window of the housing element. As the drive shaft is moved relative to the housing element by the handpiece motor, the cutting edge of the cutting head window and the opposed and facing cutting edge of the housing element window cause a cutting action which effectively severs tissue located within the housing element window and between the opposed cutting edges of the housing element and the cutting head. The configurations of these opposed edges allow for removal of particular tissue types, and a variety of different cutting window geometries are available to specifically address the type of cutting the accessory is to carry out. For example, providing the windows of both of the housing element and cutting head with straight cutting edges is useful for making fine or detailed cuts and removing areas of hard tissue, such as bone. This arrangement is often called a “straight-on-straight” cutting style or action. Alternatively, providing the windows of both the housing element and cutting head with toothed or serrated cutting edges achieves a more aggressive cut and is useful for removal of soft fibrous tissue, which arrangement is often called a “tooth-on-tooth” cutting style. A further arrangement involves providing the window of the housing element with a straight cutting edge and the window of the cutting head with a toothed cutting edge, which is often called a “tooth-on-straight” cutting style. Thus, a surgeon may often need to switch cutting accessories during a procedure in order to carry out the appropriate type or style of cut.
While the above-described surgical accessories have proven useful, when a change in cutting is desired, these accessories require the user to remove the accessory currently in use from the patient, to remove the accessory from the handpiece, install a different accessory onto the handpiece, and then reinsert the new accessory into the surgical site. Further, the known arrangements require the purchase of a multitude of accessories, which results in higher costs and a larger number of surgical accessories which must be present in the operating room in order to carry out the desired surgical procedure.
The predominant function of teeth provided on a cutting accessory, and specifically the teeth provided on the cutting head of the inner cutting element, is to pull tissue towards the cutting edge of the outer housing element, at which point the tissue is cut by means of a scissoring action between the two respective cutting edges. Even if the cutting edge of the window formed in the outer housing element is straight, the teeth of the cutting head of the inner cutting element can leave a jagged-cut finish on the tissue and/or can make grooves in the tissue. To create the cleanest finish on the tissue, the straight-on-straight scissoring or cutting style as mentioned above is typically required. However, this means that the ability of the inner cutting element to pull tissue to the cutting edge of the outer housing element is limited, which can significantly reduce the consumption rate of the surgical accessory.
In order to obviate or at least minimize disadvantages of known arrangements, the surgical accessory according to the invention provides aggressive tissue resection while still providing a smooth-cut finish on tissue resected during surgery. In this regard, the cutting window or windows located at the distal end of the cutting accessory is/are provided with alternating toothed and straight cutting edges which facilitates both aggressive and smooth cutting in one surgical cutting accessory.
Providing this type of blade geometry on a surgical accessory allows the surgeon, with a single surgical cutting accessory, to achieve a very smooth-cut finish on tissue while still being able to aggressively remove soft tissue. As such, the arrangement according to the invention reduces the number of surgical accessories that are needed during a surgery to achieve the desired result, and accordingly minimizes the need to remove the surgical accessory from the patient and then from the handpiece in order to replace same with another surgical accessory, all of which can save time during a procedure, promote safety during the procedure and reduce overall equipment costs.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction toward the end of the arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.